This invention relates to a sound emitting device for an electronic timepiece and more particularly to a sound emitting device for an electronic timepiece which permits voices to tell the time and the like.
A conventional sound emitting device has been placed on the back side in a case so as to emit some sort of sound from small sound emitting perforations furnished in the case back, as shown in U.S. Pat. No. 4,206,590. Such a device emits the sound from little clearance between the user's wrist and the case back. As a result, the sound pressure drops, causing especially low-frequency sounds to be almost inaudible.
Another type of sound emitting device now available is placed on the upper side in the case to emit the sound from the top surface of the case. See, for example, U.S. Pat. Nos. 4,167,849, 4,180,970, 4,250,573 and so on. But all of the devices are only alarm buzzers. They have limited frequency response ranges and do not enable voices to tell the time.
Electronic timepieces telling the time with voices require a sound emitting device which permits a wide frequency range of sounds to be reproduced with sufficient sound pressure. To this end, a large diameter speaker is necessary. It is difficult, however, to contain a speaker assuring sufficient sound pressure and frequency characteristics into a compact electronic timepiece. In the past, no sound emitting device has satisfied such a requirement.